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freebsd-dev/sys/vm/swap_pager.c
Doug Rabson 069e9bc1b4 Change various syscalls to use size_t arguments instead of u_int. 
Add some overflow checks to read/write (from bde).

Change all modifications to vm_page::flags, vm_page::busy, vm_object::flags
and vm_object::paging_in_progress to use operations which are not
interruptable.

Reviewed by: Bruce Evans <bde@zeta.org.au>
1998-08-24 08:39:39 +00:00

1692 lines
39 KiB
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/*
* Copyright (c) 1994 John S. Dyson
* Copyright (c) 1990 University of Utah.
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: Utah $Hdr: swap_pager.c 1.4 91/04/30$
*
* @(#)swap_pager.c 8.9 (Berkeley) 3/21/94
* $Id: swap_pager.c,v 1.99 1998/08/13 08:05:13 dfr Exp $
*/
/*
* Quick hack to page to dedicated partition(s).
* TODO:
* Add multiprocessor locks
* Deal with async writes in a better fashion
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/vmmeter.h>
#include <sys/rlist.h>
#ifndef MAX_PAGEOUT_CLUSTER
#define MAX_PAGEOUT_CLUSTER 16
#endif
#ifndef NPENDINGIO
#define NPENDINGIO 16
#endif
#define SWB_NPAGES MAX_PAGEOUT_CLUSTER
#include <vm/vm.h>
#include <vm/vm_prot.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_pageout.h>
#include <vm/swap_pager.h>
#include <vm/vm_extern.h>
static int nswiodone;
int swap_pager_full;
extern int vm_swap_size;
static int suggest_more_swap = 0;
static int no_swap_space = 1;
static int max_pageout_cluster;
struct rlisthdr swaplist;
TAILQ_HEAD(swpclean, swpagerclean);
typedef struct swpagerclean *swp_clean_t;
static struct swpagerclean {
TAILQ_ENTRY(swpagerclean) spc_list;
int spc_flags;
struct buf *spc_bp;
vm_object_t spc_object;
vm_offset_t spc_kva;
int spc_first;
int spc_count;
vm_page_t spc_m[MAX_PAGEOUT_CLUSTER];
} swcleanlist[NPENDINGIO];
/* spc_flags values */
#define SPC_ERROR 0x01
#define SWB_EMPTY (-1)
/* list of completed page cleans */
static struct swpclean swap_pager_done;
/* list of pending page cleans */
static struct swpclean swap_pager_inuse;
/* list of free pager clean structs */
static struct swpclean swap_pager_free;
static int swap_pager_free_count;
static int swap_pager_free_pending;
/* list of "named" anon region objects */
static struct pagerlst swap_pager_object_list;
/* list of "unnamed" anon region objects */
struct pagerlst swap_pager_un_object_list;
#define SWAP_FREE_NEEDED 0x1 /* need a swap block */
#define SWAP_FREE_NEEDED_BY_PAGEOUT 0x2
static int swap_pager_needflags;
static struct pagerlst *swp_qs[] = {
&swap_pager_object_list, &swap_pager_un_object_list, (struct pagerlst *) 0
};
/*
* pagerops for OBJT_SWAP - "swap pager".
*/
static vm_object_t
swap_pager_alloc __P((void *handle, vm_size_t size,
vm_prot_t prot, vm_ooffset_t offset));
static void swap_pager_dealloc __P((vm_object_t object));
static boolean_t
swap_pager_haspage __P((vm_object_t object, vm_pindex_t pindex,
int *before, int *after));
static int swap_pager_getpages __P((vm_object_t, vm_page_t *, int, int));
static void swap_pager_init __P((void));
static void spc_free __P((swp_clean_t));
struct pagerops swappagerops = {
swap_pager_init,
swap_pager_alloc,
swap_pager_dealloc,
swap_pager_getpages,
swap_pager_putpages,
swap_pager_haspage,
swap_pager_sync
};
static int npendingio;
static int dmmin;
int dmmax;
static int swap_pager_block_index __P((vm_pindex_t pindex));
static int swap_pager_block_offset __P((vm_pindex_t pindex));
static daddr_t *swap_pager_diskaddr __P((vm_object_t object,
vm_pindex_t pindex, int *valid));
static void swap_pager_finish __P((swp_clean_t spc));
static void swap_pager_free_swap __P((vm_object_t object));
static void swap_pager_freeswapspace __P((vm_object_t object,
unsigned int from,
unsigned int to));
static int swap_pager_getswapspace __P((vm_object_t object,
unsigned int amount,
daddr_t *rtval));
static void swap_pager_iodone __P((struct buf *));
static void swap_pager_iodone1 __P((struct buf *bp));
static void swap_pager_reclaim __P((void));
static void swap_pager_ridpages __P((vm_page_t *m, int count,
int reqpage));
static void swap_pager_setvalid __P((vm_object_t object,
vm_offset_t offset, int valid));
static __inline void swapsizecheck __P((void));
#define SWAPLOW (vm_swap_size < (512 * btodb(PAGE_SIZE)))
static __inline void
swapsizecheck()
{
if (vm_swap_size < 128 * btodb(PAGE_SIZE)) {
if (swap_pager_full == 0)
printf("swap_pager: out of swap space\n");
swap_pager_full = 1;
} else if (vm_swap_size > 192 * btodb(PAGE_SIZE))
swap_pager_full = 0;
}
static void
swap_pager_init()
{
int maxsafepending;
TAILQ_INIT(&swap_pager_object_list);
TAILQ_INIT(&swap_pager_un_object_list);
/*
* Initialize clean lists
*/
TAILQ_INIT(&swap_pager_inuse);
TAILQ_INIT(&swap_pager_done);
TAILQ_INIT(&swap_pager_free);
swap_pager_free_count = 0;
/*
* Calculate the swap allocation constants.
*/
dmmin = PAGE_SIZE / DEV_BSIZE;
dmmax = btodb(SWB_NPAGES * PAGE_SIZE) * 2;
maxsafepending = cnt.v_free_min - cnt.v_free_reserved;
npendingio = NPENDINGIO;
max_pageout_cluster = MAX_PAGEOUT_CLUSTER;
if ((2 * NPENDINGIO * MAX_PAGEOUT_CLUSTER) > maxsafepending) {
max_pageout_cluster = MAX_PAGEOUT_CLUSTER / 2;
npendingio = maxsafepending / (2 * max_pageout_cluster);
if (npendingio < 2)
npendingio = 2;
}
}
void
swap_pager_swap_init()
{
swp_clean_t spc;
struct buf *bp;
int i;
/*
* kva's are allocated here so that we dont need to keep doing
* kmem_alloc pageables at runtime
*/
for (i = 0, spc = swcleanlist; i < npendingio; i++, spc++) {
spc->spc_kva = kmem_alloc_pageable(pager_map, PAGE_SIZE * max_pageout_cluster);
if (!spc->spc_kva) {
break;
}
spc->spc_bp = malloc(sizeof(*bp), M_TEMP, M_KERNEL);
if (!spc->spc_bp) {
kmem_free_wakeup(pager_map, spc->spc_kva, PAGE_SIZE);
break;
}
spc->spc_flags = 0;
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
swap_pager_free_count++;
}
}
int
swap_pager_swp_alloc(object, wait)
vm_object_t object;
int wait;
{
sw_blk_t swb;
int nblocks;
int i, j;
nblocks = (object->size + SWB_NPAGES - 1) / SWB_NPAGES;
swb = malloc(nblocks * sizeof(*swb), M_VMPGDATA, wait);
if (swb == NULL)
return 1;
for (i = 0; i < nblocks; i++) {
swb[i].swb_valid = 0;
swb[i].swb_locked = 0;
for (j = 0; j < SWB_NPAGES; j++)
swb[i].swb_block[j] = SWB_EMPTY;
}
object->un_pager.swp.swp_nblocks = nblocks;
object->un_pager.swp.swp_allocsize = 0;
object->un_pager.swp.swp_blocks = swb;
object->un_pager.swp.swp_poip = 0;
if (object->handle != NULL) {
TAILQ_INSERT_TAIL(&swap_pager_object_list, object, pager_object_list);
} else {
TAILQ_INSERT_TAIL(&swap_pager_un_object_list, object, pager_object_list);
}
return 0;
}
/*
* Allocate an object and associated resources.
* Note that if we are called from the pageout daemon (handle == NULL)
* we should not wait for memory as it could resulting in deadlock.
*/
static vm_object_t
swap_pager_alloc(void *handle, vm_size_t size, vm_prot_t prot,
vm_ooffset_t offset)
{
vm_object_t object;
/*
* If this is a "named" anonymous region, look it up and use the
* object if it exists, otherwise allocate a new one.
*/
if (handle) {
object = vm_pager_object_lookup(&swap_pager_object_list, handle);
if (object != NULL) {
vm_object_reference(object);
} else {
/*
* XXX - there is a race condition here. Two processes
* can request the same named object simultaneuously,
* and if one blocks for memory, the result is a disaster.
* Probably quite rare, but is yet another reason to just
* rip support of "named anonymous regions" out altogether.
*/
object = vm_object_allocate(OBJT_SWAP,
OFF_TO_IDX(offset + PAGE_MASK) + size);
object->handle = handle;
(void) swap_pager_swp_alloc(object, M_WAITOK);
}
} else {
object = vm_object_allocate(OBJT_SWAP,
OFF_TO_IDX(offset + PAGE_MASK) + size);
(void) swap_pager_swp_alloc(object, M_WAITOK);
}
return (object);
}
/*
* returns disk block associated with pager and offset
* additionally, as a side effect returns a flag indicating
* if the block has been written
*/
static __inline daddr_t *
swap_pager_diskaddr(object, pindex, valid)
vm_object_t object;
vm_pindex_t pindex;
int *valid;
{
register sw_blk_t swb;
int ix;
if (valid)
*valid = 0;
ix = pindex / SWB_NPAGES;
if ((ix >= object->un_pager.swp.swp_nblocks) ||
(pindex >= object->size)) {
return (FALSE);
}
swb = &object->un_pager.swp.swp_blocks[ix];
ix = pindex % SWB_NPAGES;
if (valid)
*valid = swb->swb_valid & (1 << ix);
return &swb->swb_block[ix];
}
/*
* Utility routine to set the valid (written) bit for
* a block associated with a pager and offset
*/
static void
swap_pager_setvalid(object, offset, valid)
vm_object_t object;
vm_offset_t offset;
int valid;
{
register sw_blk_t swb;
int ix;
ix = offset / SWB_NPAGES;
if (ix >= object->un_pager.swp.swp_nblocks)
return;
swb = &object->un_pager.swp.swp_blocks[ix];
ix = offset % SWB_NPAGES;
if (valid)
swb->swb_valid |= (1 << ix);
else
swb->swb_valid &= ~(1 << ix);
return;
}
/*
* this routine allocates swap space with a fragmentation
* minimization policy.
*/
static int
swap_pager_getswapspace(object, amount, rtval)
vm_object_t object;
unsigned int amount;
daddr_t *rtval;
{
unsigned location;
vm_swap_size -= amount;
if (!suggest_more_swap && (vm_swap_size < btodb(cnt.v_page_count * PAGE_SIZE))) {
printf("swap_pager: suggest more swap space: %d MB\n",
(2 * cnt.v_page_count * (PAGE_SIZE / 1024)) / 1000);
suggest_more_swap = 1;
}
if (!rlist_alloc(&swaplist, amount, &location)) {
vm_swap_size += amount;
return 0;
} else {
swapsizecheck();
object->un_pager.swp.swp_allocsize += amount;
*rtval = location;
return 1;
}
}
/*
* this routine frees swap space with a fragmentation
* minimization policy.
*/
static void
swap_pager_freeswapspace(object, from, to)
vm_object_t object;
unsigned int from;
unsigned int to;
{
rlist_free(&swaplist, from, to);
vm_swap_size += (to - from) + 1;
object->un_pager.swp.swp_allocsize -= (to - from) + 1;
swapsizecheck();
}
/*
* this routine frees swap blocks from a specified pager
*/
void
swap_pager_freespace(object, start, size)
vm_object_t object;
vm_pindex_t start;
vm_size_t size;
{
vm_pindex_t i;
int s;
s = splvm();
for (i = start; i < start + size; i += 1) {
int valid;
daddr_t *addr = swap_pager_diskaddr(object, i, &valid);
if (addr && *addr != SWB_EMPTY) {
swap_pager_freeswapspace(object, *addr, *addr + btodb(PAGE_SIZE) - 1);
if (valid) {
swap_pager_setvalid(object, i, 0);
}
*addr = SWB_EMPTY;
}
}
splx(s);
}
/*
* same as freespace, but don't free, just force a DMZ next time
*/
void
swap_pager_dmzspace(object, start, size)
vm_object_t object;
vm_pindex_t start;
vm_size_t size;
{
vm_pindex_t i;
int s;
s = splvm();
for (i = start; i < start + size; i += 1) {
int valid;
daddr_t *addr = swap_pager_diskaddr(object, i, &valid);
if (addr && *addr != SWB_EMPTY) {
if (valid) {
swap_pager_setvalid(object, i, 0);
}
}
}
splx(s);
}
static void
swap_pager_free_swap(object)
vm_object_t object;
{
register int i, j;
register sw_blk_t swb;
int first_block=0, block_count=0;
int s;
/*
* Free left over swap blocks
*/
swb = object->un_pager.swp.swp_blocks;
if (swb == NULL) {
return;
}
s = splvm();
for (i = 0; i < object->un_pager.swp.swp_nblocks; i++, swb++) {
for (j = 0; j < SWB_NPAGES; j++) {
if (swb->swb_block[j] != SWB_EMPTY) {
/*
* initially the length of the run is zero
*/
if (block_count == 0) {
first_block = swb->swb_block[j];
block_count = btodb(PAGE_SIZE);
swb->swb_block[j] = SWB_EMPTY;
/*
* if the new block can be included into the current run
*/
} else if (swb->swb_block[j] == first_block + block_count) {
block_count += btodb(PAGE_SIZE);
swb->swb_block[j] = SWB_EMPTY;
/*
* terminate the previous run, and start a new one
*/
} else {
swap_pager_freeswapspace(object, first_block,
(unsigned) first_block + block_count - 1);
first_block = swb->swb_block[j];
block_count = btodb(PAGE_SIZE);
swb->swb_block[j] = SWB_EMPTY;
}
}
}
}
if (block_count) {
swap_pager_freeswapspace(object, first_block,
(unsigned) first_block + block_count - 1);
}
splx(s);
}
/*
* swap_pager_reclaim frees up over-allocated space from all pagers
* this eliminates internal fragmentation due to allocation of space
* for segments that are never swapped to. It has been written so that
* it does not block until the rlist_free operation occurs; it keeps
* the queues consistant.
*/
/*
* Maximum number of blocks (pages) to reclaim per pass
*/
#define MAXRECLAIM 128
static void
swap_pager_reclaim()
{
vm_object_t object;
int i, j, k;
int s;
int reclaimcount;
static struct {
int address;
vm_object_t object;
} reclaims[MAXRECLAIM];
static int in_reclaim;
/*
* allow only one process to be in the swap_pager_reclaim subroutine
*/
s = splvm();
if (in_reclaim) {
tsleep(&in_reclaim, PSWP, "swrclm", 0);
splx(s);
return;
}
in_reclaim = 1;
reclaimcount = 0;
/* for each pager queue */
for (k = 0; swp_qs[k]; k++) {
object = TAILQ_FIRST(swp_qs[k]);
while (object && (reclaimcount < MAXRECLAIM)) {
/*
* see if any blocks associated with a pager has been
* allocated but not used (written)
*/
if ((object->flags & OBJ_DEAD) == 0 &&
(object->paging_in_progress == 0)) {
for (i = 0; i < object->un_pager.swp.swp_nblocks; i++) {
sw_blk_t swb = &object->un_pager.swp.swp_blocks[i];
if (swb->swb_locked)
continue;
for (j = 0; j < SWB_NPAGES; j++) {
if (swb->swb_block[j] != SWB_EMPTY &&
(swb->swb_valid & (1 << j)) == 0) {
reclaims[reclaimcount].address = swb->swb_block[j];
reclaims[reclaimcount++].object = object;
swb->swb_block[j] = SWB_EMPTY;
if (reclaimcount >= MAXRECLAIM)
goto rfinished;
}
}
}
}
object = TAILQ_NEXT(object, pager_object_list);
}
}
rfinished:
/*
* free the blocks that have been added to the reclaim list
*/
for (i = 0; i < reclaimcount; i++) {
swap_pager_freeswapspace(reclaims[i].object,
reclaims[i].address, reclaims[i].address + btodb(PAGE_SIZE) - 1);
}
splx(s);
in_reclaim = 0;
wakeup(&in_reclaim);
}
/*
* swap_pager_copy copies blocks from one pager to another and
* destroys the source pager
*/
void
swap_pager_copy(srcobject, srcoffset, dstobject, dstoffset,
offset, destroysource)
vm_object_t srcobject;
vm_pindex_t srcoffset;
vm_object_t dstobject;
vm_pindex_t dstoffset;
vm_pindex_t offset;
int destroysource;
{
vm_pindex_t i;
int origsize;
int s;
if (vm_swap_size)
no_swap_space = 0;
origsize = srcobject->un_pager.swp.swp_allocsize;
/*
* remove the source object from the swap_pager internal queue
*/
if (destroysource) {
if (srcobject->handle == NULL) {
TAILQ_REMOVE(&swap_pager_un_object_list, srcobject, pager_object_list);
} else {
TAILQ_REMOVE(&swap_pager_object_list, srcobject, pager_object_list);
}
}
s = splvm();
while (srcobject->un_pager.swp.swp_poip) {
tsleep(srcobject, PVM, "spgout", 0);
}
/*
* clean all of the pages that are currently active and finished
*/
if (swap_pager_free_pending)
swap_pager_sync();
/*
* transfer source to destination
*/
for (i = 0; i < dstobject->size; i += 1) {
int srcvalid, dstvalid;
daddr_t *srcaddrp = swap_pager_diskaddr(srcobject,
i + offset + srcoffset, &srcvalid);
daddr_t *dstaddrp;
/*
* see if the source has space allocated
*/
if (srcaddrp && *srcaddrp != SWB_EMPTY) {
/*
* if the source is valid and the dest has no space,
* then copy the allocation from the srouce to the
* dest.
*/
if (srcvalid) {
dstaddrp = swap_pager_diskaddr(dstobject, i + dstoffset,
&dstvalid);
/*
* if the dest already has a valid block,
* deallocate the source block without
* copying.
*/
if (!dstvalid && dstaddrp && *dstaddrp != SWB_EMPTY) {
swap_pager_freeswapspace(dstobject, *dstaddrp,
*dstaddrp + btodb(PAGE_SIZE) - 1);
*dstaddrp = SWB_EMPTY;
}
if (dstaddrp && *dstaddrp == SWB_EMPTY) {
*dstaddrp = *srcaddrp;
*srcaddrp = SWB_EMPTY;
dstobject->un_pager.swp.swp_allocsize += btodb(PAGE_SIZE);
srcobject->un_pager.swp.swp_allocsize -= btodb(PAGE_SIZE);
swap_pager_setvalid(dstobject, i + dstoffset, 1);
}
}
/*
* if the source is not empty at this point, then
* deallocate the space.
*/
if (*srcaddrp != SWB_EMPTY) {
swap_pager_freeswapspace(srcobject, *srcaddrp,
*srcaddrp + btodb(PAGE_SIZE) - 1);
*srcaddrp = SWB_EMPTY;
}
}
}
splx(s);
/*
* Free left over swap blocks
*/
if (destroysource) {
swap_pager_free_swap(srcobject);
if (srcobject->un_pager.swp.swp_allocsize) {
printf("swap_pager_copy: *warning* pager with %d blocks (orig: %d)\n",
srcobject->un_pager.swp.swp_allocsize, origsize);
}
free(srcobject->un_pager.swp.swp_blocks, M_VMPGDATA);
srcobject->un_pager.swp.swp_blocks = NULL;
}
return;
}
static void
swap_pager_dealloc(object)
vm_object_t object;
{
int s;
sw_blk_t swb;
/*
* Remove from list right away so lookups will fail if we block for
* pageout completion.
*/
if (object->handle == NULL) {
TAILQ_REMOVE(&swap_pager_un_object_list, object, pager_object_list);
} else {
TAILQ_REMOVE(&swap_pager_object_list, object, pager_object_list);
}
/*
* Wait for all pageouts to finish and remove all entries from
* cleaning list.
*/
s = splvm();
while (object->un_pager.swp.swp_poip) {
tsleep(object, PVM, "swpout", 0);
}
splx(s);
if (swap_pager_free_pending)
swap_pager_sync();
/*
* Free left over swap blocks
*/
swap_pager_free_swap(object);
if (object->un_pager.swp.swp_allocsize) {
printf("swap_pager_dealloc: *warning* freeing pager with %d blocks\n",
object->un_pager.swp.swp_allocsize);
}
swb = object->un_pager.swp.swp_blocks;
if (swb) {
/*
* Free swap management resources
*/
free(swb, M_VMPGDATA);
object->un_pager.swp.swp_blocks = NULL;
}
}
static __inline int
swap_pager_block_index(pindex)
vm_pindex_t pindex;
{
return (pindex / SWB_NPAGES);
}
static __inline int
swap_pager_block_offset(pindex)
vm_pindex_t pindex;
{
return (pindex % SWB_NPAGES);
}
/*
* swap_pager_haspage returns TRUE if the pager has data that has
* been written out.
*/
static boolean_t
swap_pager_haspage(object, pindex, before, after)
vm_object_t object;
vm_pindex_t pindex;
int *before;
int *after;
{
register sw_blk_t swb;
int ix;
if (before != NULL)
*before = 0;
if (after != NULL)
*after = 0;
ix = pindex / SWB_NPAGES;
if (ix >= object->un_pager.swp.swp_nblocks) {
return (FALSE);
}
swb = &object->un_pager.swp.swp_blocks[ix];
ix = pindex % SWB_NPAGES;
if (swb->swb_block[ix] != SWB_EMPTY) {
if (swb->swb_valid & (1 << ix)) {
int tix;
if (before) {
for(tix = ix - 1; tix >= 0; --tix) {
if ((swb->swb_valid & (1 << tix)) == 0)
break;
if ((swb->swb_block[tix] +
(ix - tix) * (PAGE_SIZE/DEV_BSIZE)) !=
swb->swb_block[ix])
break;
(*before)++;
}
}
if (after) {
for(tix = ix + 1; tix < SWB_NPAGES; tix++) {
if ((swb->swb_valid & (1 << tix)) == 0)
break;
if ((swb->swb_block[tix] -
(tix - ix) * (PAGE_SIZE/DEV_BSIZE)) !=
swb->swb_block[ix])
break;
(*after)++;
}
}
return TRUE;
}
}
return (FALSE);
}
/*
* Wakeup based upon spc state
*/
static void
spc_wakeup(void)
{
if( swap_pager_needflags & SWAP_FREE_NEEDED_BY_PAGEOUT) {
swap_pager_needflags &= ~SWAP_FREE_NEEDED_BY_PAGEOUT;
wakeup(&swap_pager_needflags);
} else if ((swap_pager_needflags & SWAP_FREE_NEEDED) &&
swap_pager_free_count >= ((2 * npendingio) / 3)) {
swap_pager_needflags &= ~SWAP_FREE_NEEDED;
wakeup(&swap_pager_free);
}
}
/*
* Free an spc structure
*/
static void
spc_free(spc)
swp_clean_t spc;
{
spc->spc_flags = 0;
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
swap_pager_free_count++;
if (swap_pager_needflags) {
spc_wakeup();
}
}
/*
* swap_pager_ridpages is a convienience routine that deallocates all
* but the required page. this is usually used in error returns that
* need to invalidate the "extra" readahead pages.
*/
static void
swap_pager_ridpages(m, count, reqpage)
vm_page_t *m;
int count;
int reqpage;
{
int i;
for (i = 0; i < count; i++) {
if (i != reqpage) {
vm_page_free(m[i]);
}
}
}
/*
* swap_pager_iodone1 is the completion routine for both reads and async writes
*/
static void
swap_pager_iodone1(bp)
struct buf *bp;
{
bp->b_flags |= B_DONE;
bp->b_flags &= ~B_ASYNC;
wakeup(bp);
}
static int
swap_pager_getpages(object, m, count, reqpage)
vm_object_t object;
vm_page_t *m;
int count, reqpage;
{
register struct buf *bp;
sw_blk_t swb[count];
register int s;
int i;
boolean_t rv;
vm_offset_t kva, off[count];
vm_pindex_t paging_offset;
int reqaddr[count];
int sequential;
int first, last;
int failed;
int reqdskregion;
object = m[reqpage]->object;
paging_offset = OFF_TO_IDX(object->paging_offset);
sequential = (m[reqpage]->pindex == (object->last_read + 1));
for (i = 0; i < count; i++) {
vm_pindex_t fidx = m[i]->pindex + paging_offset;
int ix = swap_pager_block_index(fidx);
if (ix >= object->un_pager.swp.swp_nblocks) {
int j;
if (i <= reqpage) {
swap_pager_ridpages(m, count, reqpage);
return (VM_PAGER_FAIL);
}
for (j = i; j < count; j++) {
vm_page_free(m[j]);
}
count = i;
break;
}
swb[i] = &object->un_pager.swp.swp_blocks[ix];
off[i] = swap_pager_block_offset(fidx);
reqaddr[i] = swb[i]->swb_block[off[i]];
}
/* make sure that our required input request is existant */
if (reqaddr[reqpage] == SWB_EMPTY ||
(swb[reqpage]->swb_valid & (1 << off[reqpage])) == 0) {
swap_pager_ridpages(m, count, reqpage);
return (VM_PAGER_FAIL);
}
reqdskregion = reqaddr[reqpage] / dmmax;
/*
* search backwards for the first contiguous page to transfer
*/
failed = 0;
first = 0;
for (i = reqpage - 1; i >= 0; --i) {
if (sequential || failed || (reqaddr[i] == SWB_EMPTY) ||
(swb[i]->swb_valid & (1 << off[i])) == 0 ||
(reqaddr[i] != (reqaddr[reqpage] + (i - reqpage) * btodb(PAGE_SIZE))) ||
((reqaddr[i] / dmmax) != reqdskregion)) {
failed = 1;
vm_page_free(m[i]);
if (first == 0)
first = i + 1;
}
}
/*
* search forwards for the last contiguous page to transfer
*/
failed = 0;
last = count;
for (i = reqpage + 1; i < count; i++) {
if (failed || (reqaddr[i] == SWB_EMPTY) ||
(swb[i]->swb_valid & (1 << off[i])) == 0 ||
(reqaddr[i] != (reqaddr[reqpage] + (i - reqpage) * btodb(PAGE_SIZE))) ||
((reqaddr[i] / dmmax) != reqdskregion)) {
failed = 1;
vm_page_free(m[i]);
if (last == count)
last = i;
}
}
count = last;
if (first != 0) {
for (i = first; i < count; i++) {
m[i - first] = m[i];
reqaddr[i - first] = reqaddr[i];
off[i - first] = off[i];
}
count -= first;
reqpage -= first;
}
++swb[reqpage]->swb_locked;
/*
* at this point: "m" is a pointer to the array of vm_page_t for
* paging I/O "count" is the number of vm_page_t entries represented
* by "m" "object" is the vm_object_t for I/O "reqpage" is the index
* into "m" for the page actually faulted
*/
/*
* Get a swap buffer header to perform the IO
*/
bp = getpbuf();
kva = (vm_offset_t) bp->b_data;
/*
* map our page(s) into kva for input
*/
pmap_qenter(kva, m, count);
bp->b_flags = B_BUSY | B_READ | B_CALL | B_PAGING;
bp->b_iodone = swap_pager_iodone1;
bp->b_proc = &proc0; /* XXX (but without B_PHYS set this is ok) */
bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred;
crhold(bp->b_rcred);
crhold(bp->b_wcred);
bp->b_data = (caddr_t) kva;
bp->b_blkno = reqaddr[0];
bp->b_bcount = PAGE_SIZE * count;
bp->b_bufsize = PAGE_SIZE * count;
pbgetvp(swapdev_vp, bp);
cnt.v_swapin++;
cnt.v_swappgsin += count;
/*
* perform the I/O
*/
VOP_STRATEGY(bp->b_vp, bp);
/*
* wait for the sync I/O to complete
*/
s = splvm();
while ((bp->b_flags & B_DONE) == 0) {
if (tsleep(bp, PVM, "swread", hz*20)) {
printf(
"swap_pager: indefinite wait buffer: device: %#lx, blkno: %ld, size: %ld\n",
(u_long)bp->b_dev, (long)bp->b_blkno,
(long)bp->b_bcount);
}
}
if (bp->b_flags & B_ERROR) {
printf(
"swap_pager: I/O error - pagein failed; blkno %ld, size %ld, error %d\n",
(long)bp->b_blkno, (long)bp->b_bcount, bp->b_error);
rv = VM_PAGER_ERROR;
} else {
rv = VM_PAGER_OK;
}
splx(s);
swb[reqpage]->swb_locked--;
/*
* remove the mapping for kernel virtual
*/
pmap_qremove(kva, count);
/*
* release the physical I/O buffer
*/
relpbuf(bp);
/*
* finish up input if everything is ok
*/
if (rv == VM_PAGER_OK) {
for (i = 0; i < count; i++) {
m[i]->dirty = 0;
PAGE_CLEAR_FLAG(m[i], PG_ZERO);
if (i != reqpage) {
/*
* whether or not to leave the page
* activated is up in the air, but we
* should put the page on a page queue
* somewhere. (it already is in the
* object). After some emperical
* results, it is best to deactivate
* the readahead pages.
*/
vm_page_deactivate(m[i]);
/*
* just in case someone was asking for
* this page we now tell them that it
* is ok to use
*/
m[i]->valid = VM_PAGE_BITS_ALL;
PAGE_WAKEUP(m[i]);
}
}
m[reqpage]->object->last_read = m[count-1]->pindex;
/*
* If we're out of swap space, then attempt to free
* some whenever multiple pages are brought in. We
* must set the dirty bits so that the page contents
* will be preserved.
*/
if (SWAPLOW ||
(vm_swap_size < btodb((cnt.v_page_count - cnt.v_wire_count)) * PAGE_SIZE)) {
for (i = 0; i < count; i++) {
m[i]->dirty = VM_PAGE_BITS_ALL;
}
swap_pager_freespace(object,
m[0]->pindex + paging_offset, count);
}
} else {
swap_pager_ridpages(m, count, reqpage);
}
return (rv);
}
int
swap_pager_putpages(object, m, count, sync, rtvals)
vm_object_t object;
vm_page_t *m;
int count;
boolean_t sync;
int *rtvals;
{
register struct buf *bp;
sw_blk_t swb[count];
register int s;
int i, j, ix, firstidx, lastidx;
boolean_t rv;
vm_offset_t kva, off, fidx;
swp_clean_t spc;
vm_pindex_t paging_pindex;
int reqaddr[count];
int failed;
if (vm_swap_size)
no_swap_space = 0;
if (no_swap_space) {
for (i = 0; i < count; i++)
rtvals[i] = VM_PAGER_FAIL;
return VM_PAGER_FAIL;
}
if (curproc != pageproc)
sync = TRUE;
object = m[0]->object;
paging_pindex = OFF_TO_IDX(object->paging_offset);
failed = 0;
for (j = 0; j < count; j++) {
fidx = m[j]->pindex + paging_pindex;
ix = swap_pager_block_index(fidx);
swb[j] = 0;
if (ix >= object->un_pager.swp.swp_nblocks) {
rtvals[j] = VM_PAGER_FAIL;
failed = 1;
continue;
} else {
rtvals[j] = VM_PAGER_OK;
}
swb[j] = &object->un_pager.swp.swp_blocks[ix];
swb[j]->swb_locked++;
if (failed) {
rtvals[j] = VM_PAGER_FAIL;
continue;
}
off = swap_pager_block_offset(fidx);
reqaddr[j] = swb[j]->swb_block[off];
if (reqaddr[j] == SWB_EMPTY) {
daddr_t blk;
int tries;
int ntoget;
tries = 0;
s = splvm();
/*
* if any other pages have been allocated in this
* block, we only try to get one page.
*/
for (i = 0; i < SWB_NPAGES; i++) {
if (swb[j]->swb_block[i] != SWB_EMPTY)
break;
}
ntoget = (i == SWB_NPAGES) ? SWB_NPAGES : 1;
/*
* this code is alittle conservative, but works (the
* intent of this code is to allocate small chunks for
* small objects)
*/
if ((off == 0) && ((fidx + ntoget) > object->size)) {
ntoget = object->size - fidx;
}
retrygetspace:
if (!swap_pager_full && ntoget > 1 &&
swap_pager_getswapspace(object, ntoget * btodb(PAGE_SIZE),
&blk)) {
for (i = 0; i < ntoget; i++) {
swb[j]->swb_block[i] = blk + btodb(PAGE_SIZE) * i;
swb[j]->swb_valid = 0;
}
reqaddr[j] = swb[j]->swb_block[off];
} else if (!swap_pager_getswapspace(object, btodb(PAGE_SIZE),
&swb[j]->swb_block[off])) {
/*
* if the allocation has failed, we try to
* reclaim space and retry.
*/
if (++tries == 1) {
swap_pager_reclaim();
goto retrygetspace;
}
rtvals[j] = VM_PAGER_AGAIN;
failed = 1;
swap_pager_full = 1;
} else {
reqaddr[j] = swb[j]->swb_block[off];
swb[j]->swb_valid &= ~(1 << off);
}
splx(s);
}
}
/*
* search forwards for the last contiguous page to transfer
*/
failed = 0;
for (i = 0; i < count; i++) {
if (failed ||
(reqaddr[i] != reqaddr[0] + i * btodb(PAGE_SIZE)) ||
((reqaddr[i] / dmmax) != (reqaddr[0] / dmmax)) ||
(rtvals[i] != VM_PAGER_OK)) {
failed = 1;
if (rtvals[i] == VM_PAGER_OK)
rtvals[i] = VM_PAGER_AGAIN;
}
}
ix = 0;
firstidx = -1;
for (i = 0; i < count; i++) {
if (rtvals[i] == VM_PAGER_OK) {
ix++;
if (firstidx == -1) {
firstidx = i;
}
} else if (firstidx >= 0) {
break;
}
}
if (firstidx == -1) {
for (i = 0; i < count; i++) {
if (rtvals[i] == VM_PAGER_OK)
rtvals[i] = VM_PAGER_AGAIN;
}
return VM_PAGER_AGAIN;
}
lastidx = firstidx + ix;
if (ix > max_pageout_cluster) {
for (i = firstidx + max_pageout_cluster; i < lastidx; i++) {
if (rtvals[i] == VM_PAGER_OK)
rtvals[i] = VM_PAGER_AGAIN;
}
ix = max_pageout_cluster;
lastidx = firstidx + ix;
}
for (i = 0; i < firstidx; i++) {
if (swb[i])
swb[i]->swb_locked--;
}
for (i = lastidx; i < count; i++) {
if (swb[i])
swb[i]->swb_locked--;
}
#if defined(DIAGNOSTIC)
for (i = firstidx; i < lastidx; i++) {
if (reqaddr[i] == SWB_EMPTY) {
printf("I/O to empty block???? -- pindex: %d, i: %d\n",
m[i]->pindex, i);
}
}
#endif
/*
* Clean up all completed async pageouts.
*/
if (swap_pager_free_pending)
swap_pager_sync();
/*
* get a swap pager clean data structure, block until we get it
*/
if (curproc == pageproc) {
if (swap_pager_free_count == 0) {
s = splvm();
while (swap_pager_free_count == 0) {
swap_pager_needflags |= SWAP_FREE_NEEDED_BY_PAGEOUT;
/*
* if it does not get one within a short time, then
* there is a potential deadlock, so we go-on trying
* to free pages. It is important to block here as opposed
* to returning, thereby allowing the pageout daemon to continue.
* It is likely that pageout daemon will start suboptimally
* reclaiming vnode backed pages if we don't block. Since the
* I/O subsystem is probably already fully utilized, might as
* well wait.
*/
if (tsleep(&swap_pager_needflags, PVM-1, "swpfre", hz/2)) {
if (swap_pager_free_pending)
swap_pager_sync();
if (swap_pager_free_count == 0) {
for (i = firstidx; i < lastidx; i++) {
rtvals[i] = VM_PAGER_AGAIN;
}
splx(s);
return VM_PAGER_AGAIN;
}
} else {
swap_pager_sync();
}
}
splx(s);
}
spc = TAILQ_FIRST(&swap_pager_free);
#if defined(DIAGNOSTIC)
if (spc == NULL)
panic("swap_pager_putpages: free queue is empty, %d expected\n",
swap_pager_free_count);
#endif
TAILQ_REMOVE(&swap_pager_free, spc, spc_list);
swap_pager_free_count--;
kva = spc->spc_kva;
bp = spc->spc_bp;
bzero(bp, sizeof *bp);
bp->b_spc = spc;
bp->b_vnbufs.le_next = NOLIST;
bp->b_data = (caddr_t) kva;
} else {
spc = NULL;
bp = getpbuf();
kva = (vm_offset_t) bp->b_data;
bp->b_spc = NULL;
}
/*
* map our page(s) into kva for I/O
*/
pmap_qenter(kva, &m[firstidx], ix);
/*
* get the base I/O offset into the swap file
*/
for (i = firstidx; i < lastidx ; i++) {
fidx = m[i]->pindex + paging_pindex;
off = swap_pager_block_offset(fidx);
/*
* set the valid bit
*/
swb[i]->swb_valid |= (1 << off);
/*
* and unlock the data structure
*/
swb[i]->swb_locked--;
}
bp->b_flags = B_BUSY | B_PAGING;
bp->b_proc = &proc0; /* XXX (but without B_PHYS set this is ok) */
bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred;
if (bp->b_rcred != NOCRED)
crhold(bp->b_rcred);
if (bp->b_wcred != NOCRED)
crhold(bp->b_wcred);
bp->b_blkno = reqaddr[firstidx];
pbgetvp(swapdev_vp, bp);
bp->b_bcount = PAGE_SIZE * ix;
bp->b_bufsize = PAGE_SIZE * ix;
s = splvm();
swapdev_vp->v_numoutput++;
/*
* If this is an async write we set up additional buffer fields and
* place a "cleaning" entry on the inuse queue.
*/
object->un_pager.swp.swp_poip++;
if (spc) {
spc->spc_flags = 0;
spc->spc_object = object;
bp->b_npages = ix;
for (i = firstidx; i < lastidx; i++) {
spc->spc_m[i] = m[i];
bp->b_pages[i - firstidx] = m[i];
vm_page_protect(m[i], VM_PROT_READ);
pmap_clear_modify(VM_PAGE_TO_PHYS(m[i]));
m[i]->dirty = 0;
}
spc->spc_first = firstidx;
spc->spc_count = ix;
/*
* the completion routine for async writes
*/
bp->b_flags |= B_CALL;
bp->b_iodone = swap_pager_iodone;
bp->b_dirtyoff = 0;
bp->b_dirtyend = bp->b_bcount;
TAILQ_INSERT_TAIL(&swap_pager_inuse, spc, spc_list);
} else {
bp->b_flags |= B_CALL;
bp->b_iodone = swap_pager_iodone1;
bp->b_npages = ix;
for (i = firstidx; i < lastidx; i++)
bp->b_pages[i - firstidx] = m[i];
}
cnt.v_swapout++;
cnt.v_swappgsout += ix;
/*
* perform the I/O
*/
VOP_STRATEGY(bp->b_vp, bp);
if (sync == FALSE) {
if (swap_pager_free_pending) {
swap_pager_sync();
}
for (i = firstidx; i < lastidx; i++) {
rtvals[i] = VM_PAGER_PEND;
}
splx(s);
return VM_PAGER_PEND;
}
/*
* wait for the sync I/O to complete
*/
while ((bp->b_flags & B_DONE) == 0) {
tsleep(bp, PVM, "swwrt", 0);
}
if (bp->b_flags & B_ERROR) {
printf(
"swap_pager: I/O error - pageout failed; blkno %ld, size %ld, error %d\n",
(long)bp->b_blkno, (long)bp->b_bcount, bp->b_error);
rv = VM_PAGER_ERROR;
} else {
rv = VM_PAGER_OK;
}
object->un_pager.swp.swp_poip--;
if (object->un_pager.swp.swp_poip == 0)
wakeup(object);
if (bp->b_vp)
pbrelvp(bp);
splx(s);
/*
* remove the mapping for kernel virtual
*/
pmap_qremove(kva, ix);
/*
* if we have written the page, then indicate that the page is clean.
*/
if (rv == VM_PAGER_OK) {
for (i = firstidx; i < lastidx; i++) {
if (rtvals[i] == VM_PAGER_OK) {
pmap_clear_modify(VM_PAGE_TO_PHYS(m[i]));
m[i]->dirty = 0;
/*
* optimization, if a page has been read
* during the pageout process, we activate it.
*/
if (((m[i]->flags & (PG_WANTED|PG_REFERENCED)) ||
pmap_ts_referenced(VM_PAGE_TO_PHYS(m[i])))) {
vm_page_activate(m[i]);
}
}
}
} else {
for (i = firstidx; i < lastidx; i++) {
rtvals[i] = rv;
}
}
if (bp->b_rcred != NOCRED)
crfree(bp->b_rcred);
if (bp->b_wcred != NOCRED)
crfree(bp->b_wcred);
spc_free(spc);
if (swap_pager_free_pending)
swap_pager_sync();
return (rv);
}
void
swap_pager_sync()
{
swp_clean_t spc;
while (spc = TAILQ_FIRST(&swap_pager_done)) {
swap_pager_finish(spc);
}
return;
}
static void
swap_pager_finish(spc)
register swp_clean_t spc;
{
int i, s, lastidx;
vm_object_t object;
vm_page_t *ma;
ma = spc->spc_m;
object = spc->spc_object;
lastidx = spc->spc_first + spc->spc_count;
s = splvm();
TAILQ_REMOVE(&swap_pager_done, spc, spc_list);
splx(s);
pmap_qremove(spc->spc_kva, spc->spc_count);
/*
* If no error, mark as clean and inform the pmap system. If error,
* mark as dirty so we will try again. (XXX could get stuck doing
* this, should give up after awhile)
*/
if (spc->spc_flags & SPC_ERROR) {
for (i = spc->spc_first; i < lastidx; i++) {
printf("swap_pager_finish: I/O error, clean of page %lx failed\n",
(u_long) VM_PAGE_TO_PHYS(ma[i]));
ma[i]->dirty = VM_PAGE_BITS_ALL;
PAGE_BWAKEUP(ma[i]);
}
vm_object_pip_subtract(object, spc->spc_count);
if ((object->paging_in_progress == 0) &&
(object->flags & OBJ_PIPWNT)) {
vm_object_clear_flag(object, OBJ_PIPWNT);
wakeup(object);
}
} else {
for (i = spc->spc_first; i < lastidx; i++) {
if ((ma[i]->queue != PQ_ACTIVE) &&
((ma[i]->flags & PG_WANTED) ||
pmap_ts_referenced(VM_PAGE_TO_PHYS(ma[i])))) {
vm_page_activate(ma[i]);
}
}
}
nswiodone -= spc->spc_count;
swap_pager_free_pending--;
spc_free(spc);
return;
}
/*
* swap_pager_iodone
*/
static void
swap_pager_iodone(bp)
register struct buf *bp;
{
int i, s, lastidx;
register swp_clean_t spc;
vm_object_t object;
vm_page_t *ma;
s = splvm();
spc = (swp_clean_t) bp->b_spc;
TAILQ_REMOVE(&swap_pager_inuse, spc, spc_list);
TAILQ_INSERT_TAIL(&swap_pager_done, spc, spc_list);
object = spc->spc_object;
#if defined(DIAGNOSTIC)
if (object->paging_in_progress < spc->spc_count)
printf("swap_pager_iodone: paging_in_progress(%d) < spc_count(%d)\n",
object->paging_in_progress, spc->spc_count);
#endif
if (bp->b_flags & B_ERROR) {
spc->spc_flags |= SPC_ERROR;
printf("swap_pager: I/O error - async %s failed; blkno %lu, size %ld, error %d\n",
(bp->b_flags & B_READ) ? "pagein" : "pageout",
(u_long) bp->b_blkno, bp->b_bcount, bp->b_error);
} else {
vm_object_pip_subtract(object, spc->spc_count);
if ((object->paging_in_progress == 0) &&
(object->flags & OBJ_PIPWNT)) {
vm_object_clear_flag(object, OBJ_PIPWNT);
wakeup(object);
}
ma = spc->spc_m;
lastidx = spc->spc_first + spc->spc_count;
for (i = spc->spc_first; i < lastidx; i++) {
/*
* we wakeup any processes that are waiting on these pages.
*/
PAGE_BWAKEUP(ma[i]);
}
}
if (bp->b_vp)
pbrelvp(bp);
if (bp->b_rcred != NOCRED)
crfree(bp->b_rcred);
if (bp->b_wcred != NOCRED)
crfree(bp->b_wcred);
nswiodone += spc->spc_count;
swap_pager_free_pending++;
if (--spc->spc_object->un_pager.swp.swp_poip == 0) {
wakeup(spc->spc_object);
}
if (swap_pager_needflags &&
((swap_pager_free_count + swap_pager_free_pending) > (npendingio / 2))) {
spc_wakeup();
}
if ((TAILQ_FIRST(&swap_pager_inuse) == NULL) &&
vm_pageout_pages_needed) {
wakeup(&vm_pageout_pages_needed);
vm_pageout_pages_needed = 0;
}
splx(s);
}
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